1. Field of the Invention
The present invention relates in general to a washing machine and a control method thereof, and more particularly, to a washing machine and a control method thereof, which are improved in circulation mechanism of washing water.
2. Description of the Related Art
Recently, various washing machines have spread to a household according to the developments of washing technology such as a washing by means of air bubbles, a washing by striking the laundry with washing water, etc. Thus, the time and labor required for washing is greatly saved.
Nevertheless, there is a shortcoming that dirt is not completely removed in the case of washing white clothes. Moreover, in the case of washing underwears or baby clothes, a user wants not only a washing but also a bleaching and sterilization. Also, it is necessary to boil underwears contacting with a human body, because of an environmental contamination.
As shown in FIG. 8, a conventional washing machine having a boiling function is comprised of a cabinet 110 having a top opening 112 through which the laundry and a detergent are received; and a cover 114 opening and closing the top opening 112.
The cover 114 is comprised of an inside cover 116 for covering a heating tank 140 and an outside cover 122 above the inside cover 116.
Outside the cabinet 110 are installed a selection button 136 allowing a user to control to machine and a power controller 132 controlling a heater 150 according to a temperature signal from a temperature sensor 152.
Inside the cabinet 110 is provided the heating tank 140, being separated from the cabinet 110 by a predetermined distance, accommodating the washing and the detergent.
In the lower part of the heating tank 140 is installed the heater 150 boiling the washing by heating washing water. One side of the heater 150 is provided the temperature sensor 152 sensing a washing water temperature in the heating tank 140 heated by the heater 150. Above the heater 150 is horizontally provided a blocking plate 154 preventing the washing in the heating tank 140 from contacting with the heater 150. The blocking plate 154 has a plurality of holes 156 through which washing water flows.
With this configuration, in the conventional washing machine having the boiling function, a user puts washing water in the heating tank 140 with the washing and the detergent, and closes the inside and outside covers 116 and 122. Thereafter, the user sets up a washing time and operates the heater 150 to heat the washing water until a temperature of the washing water rises to a predetermined temperature. If the temperature of the washing water sensed by the temperature sensor 152 rises to the predetermined temperature, the heater 150 stops operating. Contrarily, if the temperature of the washing water in the heating tank 140 is lower than the predetermined temperature, the heater 150 is continuously operated to make the washing water rise to the predetermined temperature during the set up time in the power controller 132.
If the above operations continue by the set up time, then the heater 150 stops operating, and the user picks out the washing from the heating tank 140 and washes it a separate washing machine or a hand washing.
However, in the conventional washing machine having the boiling function, while the lower part of the heating tank is heated to a relatively high temperature, the upper part thereof is heated to a relatively low temperature because the washing interrupts heat transfer.
That is, even if the lower part temperature of the heating tank rises to the predetermined temperature, the upper part does not. Therefore, the temperature of the washing in the upper part of the heating tank does not reach the predetermined temperature. Consequently, the conventional boiling washing machine cannot boil the washing evenly, thereby lowering the efficiency of sterilization, bleaching and washing.
Moreover, the washing efficiency of the washing floating in washing water becomes sharply lower than to the washing efficiency of the washing soaked therein. If the temperature of washing water rises, the part of the washing contacting with air is oxidized, and therefore it may be damaged.
In addition, in the conventional boiling washing machine boiling the washing is restricted according to a material of the washing, and it is difficult to boil the washing with low temperature in the case of the washing which is not allowed to wash with a high temperature, thereby lowering the washing efficiency.
Further, since there is no drain system in the heating tank, it is required to wait until washing water becomes cool, in order that a user pumps out hot washing water with user""s own hands.
Accordingly, the present invention has been made keeping in mind the above-described shortcoming and user""s need, and an object of the present invention is to provide a washing machine and a control method thereof, which can prevent the washing from oxidizing and improve the washing efficiency.
Another object of the present invention is to provide a washing machine and a control method thereof, which can improve the washing efficiency irrespective of a material of the washing
Still another object of the present invention is to provide a washing machine and a control method thereof, which can easily supply and drain washing water.
This and other objects of the present invention may be accomplished by the provision of a washing machine comprising: a heating tank accommodating the washing and washing water; a heating part heating the washing water in the heating tank; and a circulation pump circulating the washing water in the heating tank.
Preferably, the washing machine further comprises a cabinet accommodating and supporting the heating tank, having an opening at the upper part thereof, a cover provided at the upper part of the cabinet, opening and closing the opening of the heating tank; and a controller controlling the heater to heat the washing water in the heating tank and controlling the circulation pump to circulate the washing water.
Desirably, the washing machine further comprises a control part selecting a washing course according to a washing material, and wherein the controller adjusts an operating time of the circulating pump according to the washing course selected by the control part.
Preferably, the controller controls the heating part according to the washing course selected by the control part to adjust a washing temperature, and the washing course includes a boiling course.
Preferably, the washing machine further comprises washing water circulation pipes having a washing water suction pipe communicating with one part of the heating tank, guiding the washing water from the heating tank to the circulation pump, and a washing water discharge pipe communicating with another part of the heating tank, transferring the washing water from the circulation pump to the heating tank.
Preferably, the washing water discharge pipe has at least one spray hole for spraying the washing water in the heating tank, and the washing machine further comprises a spray plate provided at the lower part of the washing water discharge pipe and having a plurality of holes for evenly supplying the washing water into the heating tank.
Preferably, the height of the washing water suction pipe is higher than the height of the heating part, and the heating part is comprised of a heater being at the below part of the heating tank.
Preferably, the washing machine further comprises a water supply pipe having a first end connected to a water supply source outside the cabinet, and a second end connected to the heating tank; and a water supply valve provided in the water supply pipe, adjusting a washing water flow in the water supply pipe.
Preferably, the washing machine further comprising a water drain pipe having a first end connected to a water drain source outside the cabinet, and a second end connected to the washing water suction pipe; and a water drain valve provided in the water drain pipe, adjusting a washing water flow in the water drain pipe, or further comprises a water drain pipe having a first end connected to a water drain source outside the cabinet, and a second end connected to the heating tank; and a water drain pump provided in the water drain pipe, draining out the washing water from the heating tank.
Preferably, outside the heating tank is provided an insulating material, and inside the cover is provided at least one pushing projection protruding inward the heating tank.
According to another aspect of the present invention, the above and other objects may be also achieved by the provision of a method for controlling a washing machine including a heater heating washing water in a heating tank, comprising the steps of supplying washing water to the heating tank; heating the washing water in the heating tank to a predetermined temperature; and circulating the washing water in the heating tank for a predetermined time.
Preferably, the method further comprises the step of draining out the washing water after circulating the washing water for the predetermined time.
Preferably, the method further comprises the step of rinsing the washing by supplying washing water again and drain out the washing water, after draining out the washing water.
Preferably, the method further comprises the steps of selecting a washing course according to a washing material; and adjusting the washing water circulating time according to the selected washing course, and the washing course includes a boiling course.
Preferably, a washing water temperature is adjusted by controlling the heater.